From scrap BBQ's to riches.
I use Petrobond sand exclusively, and here's why. the foundry sand consists of Olivine Sand, Bentonite Cla
yalong with a blend of oil. The sand is so fine you could cast your fingerprint.
With Petrobond there's no need for extra venting as it contains no water, so there's never a chance for a steam explosion as an inexperienced backyard foundry-man could have using Green Sand. The later requires a lot of upkeep, whereas with the former requires very little maintenance for perfect castings every time.
Earlier on I said that I would do some castings from that intake manifold and water jacket from that Case Diesel engine, time and other interests do not permit. So all your going to get is this short expose.
Most of my patterns came from
ebay, if I wanted a fishing weight mold I purchased the real thing, then used it for my pattern. What I soon came to realize is that I was buying castings from other back yard metal casters, the quality of the castings were not there.
For instance you should not use a fishing weight mold for a pattern that was originally die cast in a pressure mold, these types of castings have thin wall structure and are susceptible to warpage when introducing molten lead. Your lead runs out onto the ground.
Heavier wall castings, especially when used for SCUBA and Fishing weight molds, the excess aluminum acts as a heat sink - thus no warpage.
The fish mold was from a die casting procedure, look closely. The finished mold is now much heavier and thicker where it counts. How did I do that, I used auto body filler to modify the original casting.
Some of the materials I use, Plaster, Auto Body Filler, Modeling Clay, Wax, RTV Rubber, Wood and Plastic.
The scrap BBQ parts were an experiment, I no longer would even consider using this type of scrap when so much better is available.
My favorites are aluminum from engine blocks - high in silicon, outboard engines - high in copper, hydraulic pump casings, wheel rims.
To make life easier I purchased that pneumatic tamper in picture A7 below, what a time saver.
There are many different ways to make metal castings besides sand, lost foam, lost wax, pressure casting, die casting to name a few.
Lost Wax the pattern is made from wax encapsulated in plaster then burned out leaving an exact copy inside the plaster to accept the molten metal.
Lost Foam, the pattern is made by injecting tiny Styrofoam beads into a mold then injecting hot steam into the mold to expand the foam. There is a type of foam bead used by the duck hunters to make decoys.
The above description on lost foam is how the commercial foundry's do it, the backyard foundry man may just use a hot wire or simply hand carve, yes the pieces can be glued to form intricate patterns.
Next the finished foam pattern is dipped into a clay slurry, dried then packed in loose sand. Molten metal is now poured into the foam which now burns out the foam.
Pressure casting, molten metal is forced into a permanent mold, the mold is reusable many times over.
Die Casting, a slug of semi molten metal is deposited into the mold a die from above is hydraulically pressed into the hot semi molten slug which now resides in the bottom half of the mold forming the object.
Extruded Aluminum where the billet is heated via induction then forced through a die.
3D printers are the rage for making a quick pattern.
The home foundry furnace ,maybe heated using various fuels, it really does not take may BTU's to melt aluminum.
Hope you all enjoyed reading this as it's my last post tot he scrap forum, my interests in photography are demanding much of my time. It's been a blast, I've enjoyed being part of the community even though most of you deal in
e-scrap a material I have little interest in.
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